POLAR ANALYSIS OF SHORT-CRESTED MODEL WAVES.

The advent of technicallly advanced wave tanks in which the generation of short-crested waves can be controlled to a high degree opens new ways of observing and analyzing short-crested waves in the laboratory. One can reduce the number of required sensors considerably by exploiting the stationary character of the wave field in a wave tank and by expanding on suggestions to measure the sea surface elevation along straight lines in given directions. Such an approach has recently been taken by E. K. Hasle and C. T. Stansberg. To obtain the two-dimensional frequency-directional spectrum, Hasle and Stansberg used a conventional two-dimensional Fourier transformation which is performed in cartesian coordinates. However, an alternative analysis is possible which remains in the polar domain. The latter method, which is derived in this paper, has the advantage of requiring less interpolations than the former method with a correspondingly higher accuracy and saving of effort. Refs.